Re: Exposure confusion...

"KC" <kc12345@[EMAIL PROTECTED]
> wrote:

> I have a Canon S3 which does a great job setting exposure (outdoors). 
So 
> that I could take better pictures of objects, I recently purchased both
a 
> light box and a six foot wide white backdrop.  I have two 85 watt photo 
> light sources.  I tripod mount my camera.
> 
> What I want to get is a low-noise, adequately exposed image that needs 
> minimal photoshop touch up for improvement.
> 
> I am baffled that using the 85 watt lights and backdrop (or lightbox),
the 
> Canon S3 underexposes all shots and requires use of additional lighting
to 
> get proper exposure.  White backgrounds appear gray.  If I have the
camera 
> bracket exposure, the longer exposure is light enough which shows there
is 
> enough light for the camera to get a good shot, but it just isn't 
> calculating things correctly.
> 
> Because there are so many settings, I used menu/reset to reset to
factory. 
> Set the ISO to AUTO, and took photos in both P and AUTO mode.  I still
get 
> the same result.  Gray whites.
> 
> Loading an image into photoshop shows the shutter speed of 1/60 second. 
F 
> stop of 3.2 (seems high since the camera supports 2.7).  I can't tell
what 
> ISO the S3 used for the shot.
> 
> Since the Canon can adjust aperature, shutter speed and ISO, why would
it 
> constanly underexpose these images?
> 
> KC 

	In general this is what you need or wanna do.

1. Get yourself a Lighting Meter

2. Measure and Adjust your strobe(s) to meet the requirement

3. Set your camera to MANUAL and *match* the reading from Lighting Meter.

	Example you want to shoot

F.8 + ISO-100 + Shutter 100

1. Measure and adjust the strobes to hit the target above.  Or sometime
you
just want F8 + ISO-100 then lets the Shutter vary whatever works for you.

2. Then set your camera to F-8 + ISO-100 Shutter xx/yy